/*
 *    Copyright 2009-2011 the original author or authors.
 *
 *    Licensed under the Apache License, Version 2.0 (the "License");
 *    you may not use this file except in compliance with the License.
 *    You may obtain a copy of the License at
 *
 *       http://www.apache.org/licenses/LICENSE-2.0
 *
 *    Unless required by applicable law or agreed to in writing, software
 *    distributed under the License is distributed on an "AS IS" BASIS,
 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *    See the License for the specific language governing permissions and
 *    limitations under the License.
 */
package org.apache.ibatis.session;

import java.io.Closeable;
import java.sql.Connection;
import java.util.List;
import java.util.Map;

import org.apache.ibatis.executor.BatchResult;

/**
 * The primary Java interface for working with MyBatis. Through this interface
 * you can execute commands, get mappers and manage transactions.
 * 
 * @author Clinton Begin
 */
public interface SqlSession extends
		Closeable {

	/**
	 * Retrieve a single row mapped from the statement key
	 * 
	 * @param <T>
	 *            the returned object type
	 * @param statement
	 * @return Mapped object
	 */
	<T> T selectOne(String statement);

	/**
	 * Retrieve a single row mapped from the statement key and parameter.
	 * 
	 * @param <T>
	 *            the returned object type
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @return Mapped object
	 */
	<T> T selectOne(String statement,
			Object parameter);

	/**
	 * Retrieve a list of mapped objects from the statement key and parameter.
	 * 
	 * @param <E>
	 *            the returned list element type
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @return List of mapped object
	 */
	<E> List<E> selectList(
			String statement);

	/**
	 * Retrieve a list of mapped objects from the statement key and parameter.
	 * 
	 * @param <E>
	 *            the returned list element type
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @return List of mapped object
	 */
	<E> List<E> selectList(
			String statement,
			Object parameter);

	/**
	 * Retrieve a list of mapped objects from the statement key and parameter,
	 * within the specified row bounds.
	 * 
	 * @param <E>
	 *            the returned list element type
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @param rowBounds
	 *            Bounds to limit object retrieval
	 * @return List of mapped object
	 */
	<E> List<E> selectList(
			String statement,
			Object parameter,
			RowBounds rowBounds);

	/**
	 * The selectMap is a special case in that it is designed to convert a list
	 * of results into a Map based on one of the properties in the resulting
	 * objects. Eg. Return a of Map[Integer,Author] for
	 * selectMap("selectAuthors","id")
	 * 
	 * @param <K>
	 *            the returned Map keys type
	 * @param <V>
	 *            the returned Map values type
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param mapKey
	 *            The property to use as key for each value in the list.
	 * @return Map containing key pair data.
	 */
	<K, V> Map<K, V> selectMap(
			String statement,
			String mapKey);

	/**
	 * The selectMap is a special case in that it is designed to convert a list
	 * of results into a Map based on one of the properties in the resulting
	 * objects.
	 * 
	 * @param <K>
	 *            the returned Map keys type
	 * @param <V>
	 *            the returned Map values type
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @param mapKey
	 *            The property to use as key for each value in the list.
	 * @return Map containing key pair data.
	 */
	<K, V> Map<K, V> selectMap(
			String statement,
			Object parameter,
			String mapKey);

	/**
	 * The selectMap is a special case in that it is designed to convert a list
	 * of results into a Map based on one of the properties in the resulting
	 * objects.
	 * 
	 * @param <K>
	 *            the returned Map keys type
	 * @param <V>
	 *            the returned Map values type
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @param mapKey
	 *            The property to use as key for each value in the list.
	 * @param rowBounds
	 *            Bounds to limit object retrieval
	 * @return Map containing key pair data.
	 */
	<K, V> Map<K, V> selectMap(
			String statement,
			Object parameter,
			String mapKey,
			RowBounds rowBounds);

	/**
	 * Retrieve a single row mapped from the statement key and parameter using a
	 * {@code ResultHandler}.
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @param handler
	 *            ResultHandler that will handle each retrieved row
	 * @return Mapped object
	 */
	void select(String statement,
			Object parameter,
			ResultHandler handler);

	/**
	 * Retrieve a single row mapped from the statement using a
	 * {@code ResultHandler}.
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param handler
	 *            ResultHandler that will handle each retrieved row
	 * @return Mapped object
	 */
	void select(String statement,
			ResultHandler handler);

	/**
	 * Retrieve a single row mapped from the statement key and parameter using a
	 * {@code ResultHandler} and {@code RowBounds}
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to use.
	 * @param rowBounds
	 *            RowBound instance to limit the query results
	 * @param handler
	 *            ResultHandler that will handle each retrieved row
	 * @return Mapped object
	 */
	void select(String statement,
			Object parameter,
			RowBounds rowBounds,
			ResultHandler handler);

	/**
	 * Execute an insert statement.
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to execute.
	 * @return int The number of rows affected by the insert.
	 */
	int insert(String statement);

	/**
	 * Execute an insert statement with the given parameter object. Any
	 * generated autoincrement values or selectKey entries will modify the given
	 * parameter object properties. Only the number of rows affected will be
	 * returned.
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to execute.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @return int The number of rows affected by the insert.
	 */
	int insert(String statement,
			Object parameter);

	/**
	 * Execute an update statement. The number of rows affected will be
	 * returned.
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to execute.
	 * @return int The number of rows affected by the update.
	 */
	int update(String statement);

	/**
	 * Execute an update statement. The number of rows affected will be
	 * returned.
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to execute.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @return int The number of rows affected by the update.
	 */
	int update(String statement,
			Object parameter);

	/**
	 * Execute a delete statement. The number of rows affected will be returned.
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to execute.
	 * @return int The number of rows affected by the delete.
	 */
	int delete(String statement);

	/**
	 * Execute a delete statement. The number of rows affected will be returned.
	 * 
	 * @param statement
	 *            Unique identifier matching the statement to execute.
	 * @param parameter
	 *            A parameter object to pass to the statement.
	 * @return int The number of rows affected by the delete.
	 */
	int delete(String statement,
			Object parameter);

	/**
	 * Flushes batch statements and commits database connection. Note that
	 * database connection will not be committed if no updates/deletes/inserts
	 * were called. To force the commit call {@link SqlSession#commit(boolean)}
	 */
	void commit();

	/**
	 * Flushes batch statements and commits database connection.
	 * 
	 * @param force
	 *            forces connection commit
	 */
	void commit(boolean force);

	/**
	 * Discards pending batch statements and rolls database connection back.
	 * Note that database connection will not be rolled back if no
	 * updates/deletes/inserts were called. To force the rollback call
	 * {@link SqlSession#rollback(boolean)}
	 */
	void rollback();

	/**
	 * Discards pending batch statements and rolls database connection back.
	 * Note that database connection will not be rolled back if no
	 * updates/deletes/inserts were called.
	 * 
	 * @param force
	 *            forces connection rollback
	 */
	void rollback(boolean force);

	/**
	 * Flushes batch statements.
	 * 
	 * @return BatchResult list of updated records
	 * @since 3.0.6
	 */
	List<BatchResult> flushStatements();

	/**
	 * Closes the session
	 */
	void close();

	/**
	 * Clears local session cache
	 */
	void clearCache();

	/**
	 * Retrieves current configuration
	 * 
	 * @return Configuration
	 */
	Configuration getConfiguration();

	/**
	 * Retrieves a mapper.
	 * 
	 * @param <T>
	 *            the mapper type
	 * @param type
	 *            Mapper interface class
	 * @return a mapper bound to this SqlSession
	 */
	<T> T getMapper(Class<T> type);

	/**
	 * Retrieves inner database connection
	 * 
	 * @return Connection
	 */
	Connection getConnection();
}
